GAMMARELLA BREVICAUDATA. 331 



suddenly to decrease in size. The eyes are small and 

 round. The superior antennas are about half the length 

 of the animal ; the flagellum is about the same length as 

 the peduncle ; the secondary appendage consists of four 

 articuli. The inferior antennas scarcely reach beyond 

 the extremity of the peduncle of the superior ; the 

 flagellum is not longer than the last joint of the ped- 

 uncle. The first pair of legs are very small and slender. 

 The second, as if to compensate for the insignificant 

 character of the first, are extremely large, the hand 

 being nearly equal in length to the head and first three 

 segments of the body, it is of a long oval form, slightly 

 tapering to the distal extremity ; the palm occupies the 

 whole length of the inferior margin : the finger is very 

 long and robust, and the wrist is extremely short. The 

 last three pairs of legs have the thighs dilated into 

 broadly oval plates ; and the fingers are short and strong, 

 and articulated, with the hands at the anterior margin of 

 the distal extremity. The caudal appendages are short, 

 the branches being shorter than the peduncles, the last 

 being single branched, a strong spine being probably the 

 rudiments of the obsolete second branch. The central 

 tail-piece is broad, divided nearly to the base, having 

 each division subapically crowned with a short spine. 



The animal is of a dark olive -green colour. Under 

 the microscope the surface is seen to be covered with 

 stiff hairlike processes and spots ; these last being the 

 result of small groups of little spinules. 



We have but little hesitation in referring Gammarus 

 punctimanus of Costa to this species, although that author 

 represents the upper antennas as destitute of a supple- 

 mental appendage. 



The animal was first taken at Morbihan, on the coast 

 of France, by M. Milne Edwards. It has since been 



